Device for bending a workpiece



May 5, 1970 Y E. HNNI l 3,509,757

i DEVICE FOR BENDING A woRKPIEcE Filed Oct. 12. 1964 5 Sheets-Sheet 1May 5, 1970 E. HNNI 3,509,757

` DEVICE FOR BENDING A WORKPIECE Filed Oct. 12', 1964 3 Sheets-Sheet 2III I Illll May 5, 1970 E. HNNI DEVICE FOR BENDING A WORKPIECE 5Sheets-Sheet 5 Filed Oct. 12. 1964 /n u-ef/ for United States i. Patentll() U.S. Cl. 72-414 2 Claims ABSTRACT `oir Tirs. DISCLOSURE The presentinvention concerns a device for bending a workpiece which device issuitable for carrying out bending work according to a pre-determinedprogramme.

Hitherto, in such operations, interchangea'ble bending parts which canbe connected with the ram or table of a `press have been used, the partsbeingchanged after each step of the operation.

This procedure is both uneconomical and` time-consuming and isparticularly disadvantageous in the mass production of sheet metalpieces.

The present invention provides a device for bending work having amovable ram and a work table characterised in that a tool holder issecured on both the ram and work table, at least one of the tool holdershaving various bending tools which can be moved from a position ofreadiness into the working position, and whereby for each tool in thetool holder on the ram a complementary tool is provided in the toolholder arranged on the table.

The tool holders may conveniently be constructed as revolving heads andbe adapted to pivot from the insertion position into a position foreffecting the change of tools.

The invention will be further apparent from the following descriptionand the several gures of the accompanying drawings which show, by way ofexample two presses embodying the invention.

In the drawings,

FIG. 1A shows a tool set secured to the ram of the first press;

FIG. 1B shows the complementary tool set secured to the working table ofthe rst press; and

FIG. 2 shows the second press.

Referring now to FIGS. 1 and 2, it will be seen that the ram of thebending device is indicated by the reference numeral 1.

The ram 1 is provided with a centering stop 2 having a centering face 3against which a corresponding face of.` a tool set is located. The toolset is constructed as a revolving tool holder 4 and is provided withinsertable tools.

As shown in the drawing, three tool inserts 5, 6 and 7 are provided,which have differently shaped profiles that enable a workpiece to bebent at different angles. The tool holder 4 is rotatably mounted on anaxle 8i, which is held at each end by a lever arm 9. The lever arms 9(only one of which is visible in the drawing) are pivotally mounted inthe frame of the ram, for example, on an axle 10, the end of each leverarm remote from the axle 8 being in connection with an actuating rod 11.The rod 11 is connected with a piston (not shown) of a cylinder 12pivotally mounted on an axle 14 in a housing 13 of the ram. In this way,on actuation of the piston in the direction of the arrow P into thecylinder 12, the lever arms 9 are pivoted counter-clockwise so that thetool holder 4 is pivoted from the working position into thetool-changing position shown by dash-dot lines. In this position thetool holder 4 can be so rotated that the tools rice 5, 6 or 7 can bebrought into their working position. The operation of the piston in thecylinder 12 takes place pneumatically.

l An analogous arrangement is present on the table 14 (FIG. 1B) of thedevice of FIGS. lA and 1B, which again has a centering stop 15 againstwhose centering face 16 a corresponding face 17 of a tool holder 18comes to rest. The tool holder 18 is mounted to rotate on an axle 19 andhas tool inserts 20, 21 and 22 which `are intended to co-operate withthe tools 5, 6 and 7.

The axle 19 of the tool holder 18 is held at each side by a two-armedlever 23 (only one such lever 23y being shown in the drawing).

Each lever 23 is pivotally mounted on an axle 24 and is connected at theopposite end with an actuating bar 25 of a piston to reciprocate in acylinder 26. The cylinder 26 is pivotally mounted on an vaxle 27 in thehousing 28. Similarly to the levers 9, the pair of levers 23 can bepivoted so that the tool holder 18 takes up the position shown bydash-dot lines. In this position, the tool holder 18 can be turned sothat the tools 20, 21 or 22 can be i `brought into their workingposition. When the pair of levers 23 is swung into the working position,an automatic centering of the tool holder 18 take-s place in that thecorresponding face 17 will rest against the centering surface 16.

In this way, continuous and very rapid working is achieved whereby aftereach bending process the tool holders 4 and/or 18 are swung out and thetools changed by rotation of the tool holders. The pivoting of thelevers 9 or 23 takes place in opposite directions, i.e. the levers 9 arepivoted counter-clockwise, and the levers 23 clockwise, so that the toolholders 4 and 18 are laterally off set with respect to one another inthe pivoted position. In this way, free space is made available for thechange of tools so that on rotation of the tool holders, the parts 5, 6,7 cannot collide with the parts 20, 21, 22.

A further embodiment of the invention is shown in FIG. 3. This is achamfering press having a bending device for the carrying out ofconsecutive operations, for example, multiple bends. The bending devicehas a table 30 with a tool holder 51 which carries a matrix 31. Thematrix is provided with two forms ,32 and 33 which cooperate with twopress dies 34 and 35. The die 34 is ex changeably mounted on a toolholder 36 of the ram of the bending device by means of a screw bolt 37and is provided with a die holder 38 which carries the die 35 that ispivotally mounted on an axle 39 of the holder 38 yso that the die 35 canbe pivoted out of the solid line position into one shown by dash-dotlines. The position of the die 35 shown in solid lines corresponds tothe working position while the dash-dot line position corresponds to theinoperative position of the die 35.

For the operation of the die 35 an air cylinder 40 is provided which ispivotally secured to the tool holder 36 by means of a forleshaped holder52. The cylinder has a piston which has a piston rod 41 that isconnected with an arm 43 by means of a fork shaped holder 42. This arm43 is connected by a screw bolt 44 with the pivoting die 35.

On operation of the air cylinder 40 which whereby it is pivotedclockwise in the fork shaped holder 52, the die 35 can be brought fromthe working position into the inoperative position.

In this way it is possible to work selectively with both dies or withonly one die. Adjustable bolts 45 and 46 which are mounted for axialadjustment by means of a threaded spindle 48 in a holder 47 areprovided. The bolts 45 and 46 act as stops for the piece 49 to be workedand conveniently fed through corresponding bores in the matrix 31. Theholder 47 is supported in a pedestal 50` of the device.

,.- A f l3 What I claim is: :""I devicor bending" Work," comprising:

(a) a movable ram, (b) a Work table, Y l (c) two toolholders, one ofsaid tool holders being secured to said ram and said work table,respectively, vat least one of said tool holders being mounted to be imovable from a tool-exchanging position into a Working positionand viceversa,

' (11) each of said tool holders being rotatably mounted in a pair oftwo-armed levers, each of said pairs of levers being responsive to anactuating rod, each of said rods' being attached i to a pneumaticallyoperable piston, andthus causing pivoting ofthe pairso'f levers fromsaid working position to said tool-exchanging posil l tion, and

(d) bending tools held in said tool holders, whereby i Y foreach.bending tool provided in the'tool holder of said ram there is acomplementary tool in the tool holder of said work table. f2. A devicefor bending work, comprising: (a) a movable ram, f (b) a work table, (c)two tool holders, one of said tool holders being secured to said ram andworktable respectively, at least one of said tool holders being mountedto be movable from a tool-exchanging position into a workingposition andvice versa',

(1) each of said tool holders being rotatably mounted in a pair oftwo-armed levers, each of said pairs of levers being responsive to anactuatingrod?. each of said rods being attached to a pneumaticallyoperable piston, and thus causing pivoting lof the pairs of levers fromsaid working position to said tool-exchanging position, and Y (.2) saidlevers and said pistons being arranged to pivot said pairs of levers inopposite direction, and (d) bending tools held in said tool holders,whereby for .each bending tool .providedrin the tool holder of said ramthere is a complementary tool inthe tool holder ofsaid work table.

References Cited UNITED STATES PATENTS 2,426,446 V8/ 1947 Funk r..72-412 2,456,749 12/ 1948 Steibel 'i2-412 2,847,053 .8/ 1958 Hardman7.2-414 3,029,858 4/ 1962 Harper i -72-412 yCI'IRLES W. LANHAM, PrimaryExaminer M. J. KEENAN, Assistant Examiner

